Improvement in induction-coils



J. KIDDER. INDUCTION GOIL.

No. 52,054. Patented Jan.16, 1866.

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DR. JEROME KIDDER,

IMPROVEMENT IN PATENT OFFICE.

OF NEW YORK, N. Y.

lNDUCTlON-COlLS.

Specification forming part of Letters Patent No. 62,054, dated January16, 1866.

To all whom it may concern:

Be it known that I, JEROME KIDDER, of the city, county, and State of NewYork, have invented a new and useful Improvement in the Method ofObtaining Induced Currents of Electricity from Magnets andInduction-Coils; and I do hereby declare that the following is a full,clear, and exact description of the same, reference being had to theaccompanying drawings, forming part of this specification.

I have made the discovery that the central or so-called neutral portionof a magnetthat part which has no attractive poweris where the strongestinduced current results in using over it a helix or helices of insulatedwire; and this invention consists. in the practical application of suchdiscoveryviz.. in arranging. the insulated wire which composes the helixor helices by which the induced current or currents are obtained, eitherwholly or in greater quantity, at or near that portion of the magnet,instead of, in the usual manner, evenly distributed along the wholelength of the magnet, or wholly or in greater quantity near the polesthereof.

The advantages of this arrangement are, first, when 1 wish to obtaininduction-currents froma long magnet (which resumes its unmagnetizedstate slower than a short one when the primary current is broken) I getastronger inductiomcurrent on the same magnet by winding the finewiresubstantially as above; see- 0nd,with a given size of wire for theprimary coil of a given number of layers(not convolutions) I am enabledto get strong induction-currents without so great a draft or drawing 0Ethe power of the battery and weakeningthe solution, because there is alonger primary wire interposed so as to exert its force on the magnetwithout necessitating the location of the fine wire at a fartherdistance from the magnet; third, it enables me to suspend a heavyhelix-binding. N, in ahlock of wood or other manner at the end withoutinterference from fine wire, over which latter a tube to receive withinitself the induction force can be placed to weaken or cut oi? thecurrent from the coil or coils.

The invention further consists in making the said helix or helicesadjustable lengthwise of the magnet, for the purpose, when desired, ofvarying the power of the current by bringing the said helix or helicesnearer to or farther from. the so-called neutral portion of the magnet.

Figure 1 in the drawings is a plan or top View of an electro-magnet,having upon it two helices for obtaining induced currents,one placed inthe usual position near one of the poles of the magnet and the otherplaced on the neutral portion of the magnet near the longitudinal centerthereof, according to my invention. Fig. 2 is a longitudinal verticalsection corresponding-with Fig. 1.

Similar letters of reference indicate corresponding parts in both ofthese figures.

G is a core, composed of a bundle of iron wires, around which iswound,in two layers,a helix, S, of coarse insulated copper wire, oneend, 70, of which is connected with the metal post E, and the otherend,'l, is connected with the metal post F. The said posts are supportedin the wooden base T, to which arealso secured the supports a a of thecore G and two posts, A and B. The posts A and F are connected, one withthe positive and the other with the negative pole of a galvanic battery,the primary current from which passes from the positive pole of thebattery through the post A, along the wire M, under the base T, to thepost B, thence along the screw 0 in the said post,from its platinumpoint to the spring D of the hammer H, and through the said spring andits supporting-post E to the end k of the helix, of coarse insulatedcopper wire, through the entire length of the said helix, and out at l,thence through the post F to the negative pole of the battery. Thisbatterycurrent magnetizes the core G.

U and 0 are two outer helices for obtaining induced currents ofclectricii y. These helices are made of fine insulated copper wire,which is coiled in several layers around spools of wood placed over thehelix S. The wire of the helix U begins at V and terminates in the loopQ, where the wire of the helix 0 commences, and the latter terminates atR.

The primary current from the battery is interrupted by the magnet Grattracting the hammer H so as to draw the spring D away from the screw0, and as this opens the circuit the core Gr resumes its unmagnetizedstate, and at the same moment there is an induced current in the helicesU and 0, that in 2 times;

great power. The spools are movable lengthwise upon the magnet, so thatthe power of the induced current in their helices may be varied,thecurrents beingweak when they are fat or near thepoles ofthe'magnetand stronger as they are moved nearer to the center of the length of themagnet, the maximum power being obtained whenthey are at the center ofthe length of the magnet and the minimum power when they are close tothe poles.

The induction-coil, instead of being made movable upon the magnet, asabove described, may be fixed thereon at and near the center of itslength, as shown in Fig. 3, which is a central longitudinal section ofthe magnet. in this figure G is the core, S the coil of coarse insulatedwire through which 'the primary current passes, and U theinduction-coil. In a magnet having the induction-coil thus fixed theforce of theinduction-current maybe varied by means of a cylindricalcap, V, of metal, fitted to. slide over one end of the magnet and overthe induction-coil, and to permit the application of this-cylindricalcap the magnet must have a support, W,'atone end only.

WVhat I claim as new, and desire to secure by Letters Patent, is"

1. Arranging the fine insulated wire which composesthe helix or helicesused upon a magnet tbrphtaining an induced current or currents, eitherwholly or in greater quantity,

at or near the centerof the length of the magnet, or what is termed itsneutral portion, in combination with the arrangement of the inner orprimary coil, S, and its core of soft-iron G, substantially as and forthe purpose specified.

2.- Making the said helix or helices adjust able upon the magnet betweenthe poles and the so-called neutral portion thereof, for the purpose ofvarying the power of the induced current or current-s, substantially asdescribed.

DR. JEROME KIDDER. Witnesses:

J W. Goorms, GEo. W. REED.

